25 years ago I was working on DEC’s earliest RAID array. When I look at today’s “high-end” arrays, it’s shocking how little architectural change the big iron arrays have embraced.
The industry is ripe for disruption, only part of which is coming from cloud vendors. 21st century problems demand 21st century architectures.
Here’s a list of the obsolete technologies still embraced by most large arrays.
RAID. After it turned out that the governing assumption behind RAID was not accurate – non-correlated failures – and as drive sizes increased, RAID data losses and rebuild times are both too high. Rebuild times have rendered traditional RAID 5 and 6 enterprise arrays functionally obsolete.
Active/active controllers. CPU cycles used to be costly. Now they’re cheap. If performance and availability are paramount, triple controllers – active/active/active – or better are the way to go.
Low density drive enclosures. Why do we need to install drives at a moment’s notice? RAID. Drive failures in a stripe – even with RAID 6 – threaten data integrity due to failure correlation and silent data corruption. Get rid of RAID in favor of modern redundancy techniques and drive replacements can be handled by calm, awake people.
Fiber channel drives. With the rise of much faster SSDs with dual SAS connectors there is little reason for fiber channel drives. Dump ’em.
Hot spares. Parking an expensive and wearing resource in an expensive slot – and not using it – was a good idea only compared to the alternatives. Getting rid of RAID means that all of your unused capacity can be used for fast replication, not just dedicated drives.
Back up. Enterprise storage should be engineered to make back up unnecessary. We know how to do it, it’s been done, data sizes are exploding and back up windows are imploding.
Custom hardware. Hardware, formerly a differentiator, is now a boat anchor. Low-volume, costly, and little benefit. FPGAs and ASICs make sense for the bleeding edge, but if you aren’t using high-volume hardware for 98% of your kit, you’re last century.
The StorageMojo take
Storage has always been conservative – almost as conservative as the backup and archive. Your data is, after all, why you invest in infrastructure.
But the “new” technologies that have rendered old architectures obsolete are now 10 years old. Times have changed.
Object storage is powering the world’s largest storage systems – and they aren’t using RAID either. That makes high-density drive enclosures – 45-60 drives in 4U – feasible.
Chunk data across enough drives or use SSDs and you don’t need fibre-channel drives. With advanced erasure codes and fast snapshots you can lose backup too – and the expense of the systems it requires. Archiving remains a different problem.
All this and more without custom hardware. Server-hosted storage works as Google, Amazon and Azure have proven.
In five years these old architectures should be on the ash heap of history. But they won’t, because too many buyers buy what makes them comfortable, rather than what maximizes utility at the lowest cost.
But as those folks retire or get eased out, the market change will accelerate.
Courteous comments welcome, of course. What’s your favorite obsolete array technology?